Device tree bindings for OMAP general purpose memory controllers (GPMC)

The actual devices are instantiated from the child nodes of a GPMC node.

Required properties:

 - compatible:		Should be set to one of the following:

			ti,omap2420-gpmc (omap2420)
			ti,omap2430-gpmc (omap2430)
			ti,omap3430-gpmc (omap3430 & omap3630)
			ti,omap4430-gpmc (omap4430 & omap4460 & omap543x)
			ti,am3352-gpmc   (am335x devices)

 - reg:			A resource specifier for the register space
			(see the example below)
 - ti,hwmods:		Should be set to "ti,gpmc" until the DT transition is
			completed.
 - #address-cells:	Must be set to 2 to allow memory address translation
 - #size-cells:		Must be set to 1 to allow CS address passing
 - gpmc,num-cs:		The maximum number of chip-select lines that controller
			can support.
 - gpmc,num-waitpins:	The maximum number of wait pins that controller can
			support.
 - ranges:		Must be set up to reflect the memory layout with four
			integer values for each chip-select line in use:

			   <cs-number> 0 <physical address of mapping> <size>

			Currently, calculated values derived from the contents
			of the per-CS register GPMC_CONFIG7 (as set up by the
			bootloader) are used for the physical address decoding.
			As this will change in the future, filling correct
			values here is a requirement.

Timing properties for child nodes. All are optional and default to 0.

 - gpmc,sync-clk:	Minimum clock period for synchronous mode, in picoseconds

 Chip-select signal timings corresponding to GPMC_CONFIG2:
 - gpmc,cs-on:		Assertion time
 - gpmc,cs-rd-off:	Read deassertion time
 - gpmc,cs-wr-off:	Write deassertion time

 ADV signal timings corresponding to GPMC_CONFIG3:
 - gpmc,adv-on:		Assertion time
 - gpmc,adv-rd-off:	Read deassertion time
 - gpmc,adv-wr-off:	Write deassertion time

 WE signals timings corresponding to GPMC_CONFIG4:
 - gpmc,we-on:		Assertion time
 - gpmc,we-off:		Deassertion time

 OE signals timings corresponding to GPMC_CONFIG4:
 - gpmc,oe-on:		Assertion time
 - gpmc,oe-off:		Deassertion time

 Access time and cycle time timings corresponding to GPMC_CONFIG5:
 - gpmc,page-burst-access: Multiple access word delay
 - gpmc,access:		Start-cycle to first data valid delay
 - gpmc,rd-cycle:	Total read cycle time
 - gpmc,wr-cycle:	Total write cycle time

The following are only applicable to OMAP3+ and AM335x:
 - gpmc,wr-access
 - gpmc,wr-data-mux-bus


Example for an AM33xx board:

	gpmc: gpmc@50000000 {
		compatible = "ti,am3352-gpmc";
		ti,hwmods = "gpmc";
		reg = <0x50000000 0x2000>;
		interrupts = <100>;

		gpmc,num-cs = <8>;
		gpmc,num-waitpins = <2>;
		#address-cells = <2>;
		#size-cells = <1>;
		ranges = <0 0 0x08000000 0x10000000>; /* CS0 @addr 0x8000000, size 0x10000000 */

		/* child nodes go here */
	};